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TwoBitTxn
November 13th, 2001, 06:27 PM
Help please...

A J valve is the single knob job that is most commonly seen on aluminum tanks right?

A K valve has two knobs right?

What do the two knobs do?

Why the difference?

Tom

large_diver
November 13th, 2001, 06:50 PM
Close -- K valve is the common "one knob" valve you see on most tanks today.

I've never actually seen a J, but have read about them before. See link below for a pic and description.
http://www.diverlink.com/gear/earlygear.htm

Rick Murchison
November 13th, 2001, 08:16 PM
The "K" valve is the standard on/off valve commonly seen on most tanks.
The "J" valve has a lever that when raised cuts off airflow at about 300 psi - by lowering the lever you gain access to the last 300 psi. This valve was used before the advent of the SPG as an emergency indicator it was time to end the dive.
The "H" valve has two independently controlled orifices and will accept two first stage regulators. Many will accept both DIN and Yoke regs (via a yoke insert). HP variety are DIN only.
The "Y" valve is like the "H" valve but older, and less common today as the "H" valve can be adapted to a manifold for doubling tanks where the "Y" valve can't.
Rick

NetDoc
November 13th, 2001, 08:42 PM
The "Dump Valve" used in the Warhammer Manouver... Unlike the others it HAS to be O2 cleaned for all environments... I almost forgot the Bivalve... which exist on many an ocean floor. And the Valve-salva manouver... Then there's the stuff to lube all of these valves, aka valve-oline. Does anyone still drive a Valvo??? Sorry, just got a bit over in-valved in the process...

Ontario Diver
November 13th, 2001, 08:57 PM
Good answer Rick, just let me add a little bit.....


Originally posted by Rick Murchison
The "K" valve is the standard on/off valve commonly seen on most tanks.
The "J" valve has a lever that when raised cuts off airflow at about 300 psi - by lowering the lever you gain access to the last 300 psi. This valve was used before the advent of the SPG as an emergency indicator it was time to end the dive.
The "H" valve has two independently controlled orifices and will accept two first stage regulators. Many will accept both DIN and Yoke regs (via a yoke insert). HP variety are DIN only.
The "Y" valve is like the "H" valve but older, and less common today as the "H" valve can be adapted to a manifold for doubling tanks where the "Y" valve can't.
Rick

Most rental "J"'s have been modified to remove the lever action and function just like a "K".

The names come from the item numbers that were used to identify the valve in the early catalogs. (A "L" valve was item L; the "K" valve was item K, etc.)

TexasMike
November 13th, 2001, 08:58 PM
Pete....

And in one way(valve), I always keep the butterfly(valves) close to my heart(valves).


Sorry...couldn't resist the very obvious pun(valve).

NetDoc
November 13th, 2001, 09:29 PM
I think I o-puned a can of worms... yeah, yeah, I know I am one to puntificate... remember I valve-u our friendship, so I will be quiet now... As Vince Lombardi once said... "When in doubt, Pun!"

TwoBitTxn
November 13th, 2001, 11:41 PM
Ok I think I understand, but I'll try to describe what I have and get some one to explain what I got.

I picked up a tank that has a knob on one side that is obviously the on/off. It has another knob 180* from it with the port in the middle. What do I have and what does the other knob do?

The tank needs a hydro and is empty. So I can't fill it to find out.

Tom

miked
November 14th, 2001, 12:12 AM
Tom,
This is a semi-wild, semi-educated guess, but you might have a "J-valve" ,with function as accurately described by Rick.
Does the knob opposite the "on /off" knob have anything that looks like an attachment point for a hook ended rod?(a small hole or "eyelet"?)If so, that would be a stronger indicator that you have a "J valve". I also remember being told that the "other" knob was there for ease of carrying- but that always sounded a little strange, as we were simultaneously being told to not carry the tank by the valve.

OD, I hadn't heard the "catalog" source for the names of the different type valves before this. I recall being told that the J valve got its name from the shape of the rod used to activate the reserve PSI in the tank, and that the "Y valve" and "H valve" were so named because of their shape. (I must confess, I've never seen an H valve, so I can't judge the accuracy of that part of the claim.)
In any event, its interesting how these different interpretations occur.
Take care,
Miked

NetDoc
November 14th, 2001, 12:44 AM
A "J" valve. The knob (usually on top) opens the tank valve, the other lever (which only goes so far) is the "safety mechanism". That being said, if the tank hydros out, I would replace that valve with a newer "K" valve. BTW, the story about the catalogue is true for the H, K, and J valves... the Y get's it name from it's shape.

Walter
November 14th, 2001, 08:42 AM
The J & K getting their names from the US Divers Catalog (1953?) is true, although I'm pretty sure the H got its name (as did the Y) from its shape.

Sounds like you have a J valve. Does the extra knob have a tab on it? Does this knob only turn about 45 - 50°?

I've never seen a J valve with the knob on the top, all of those I've seen were K valves.

As long as your J valve is in good condition there's no reason to replace it.

DSSW,

WWW™

TwoBitTxn
November 14th, 2001, 04:44 PM
Thanks everyone.

Yes the knob has a little tab on it with a hole and it doesn't turn very far. The shop where I took it to get hydro'ed confirmed it was a J valve. I really don't see any reason to replace it. It just looks different from all the other valves and it will make it easier to find in a cluster of tanks. It all looks in really good condition.

Thanks again.

Tom

Ontario Diver
November 14th, 2001, 05:08 PM
Tom;

Most of the J's that I see have been changed to Ks by having the second valve removed and plugged. Might be worthwhile to have the shop do it at some point so you don't "lose" 300 PSI while diving some day.

NetDoc
November 14th, 2001, 05:19 PM
With OD! Thats why they always give me the heebie jeebies when I see one. All you need is some kid playing with it with out your knowledge. Walter, I have one that I took out of service and the valve is on top with the switch a lot lower and on the side.

Walter
November 14th, 2001, 09:09 PM
Pete, thanks. I've never seen one, but there's lots of gear I've never seen being a relative new comer to the sport.

DSSW,

WWW™

NetDoc
November 14th, 2001, 09:52 PM
Sarcasm does not become you. Should I take a picture of it for you??? I am sure that I can get hold of a digital camera to do that. It is an "AMF" valve and has a tiny little "T" on the top for the valve, and the switch is a stubby lever with a hole drilled in it about 2" or so below the valve. It came off of a steel 72, that I don't own anymore.

Walter
November 14th, 2001, 10:04 PM
Pete, I was serious - no sarcasm. There is lots of gear I haven't seen. I enjoy learning about other things. I mean it - Thank you.

DSSW,

WWW™

TwoBitTxn
November 14th, 2001, 10:59 PM
All the valve does is cut off access to the last 300-500psi correct? I check it the same as I check to make sure my air is on and all is ok. I don't understand how replacing it would be a priority.

Tom

Ontario Diver
November 14th, 2001, 11:18 PM
Tom;

The problem is that some of the older valves can stick or slide.

The way that the J valve works is at the beginning of the dive the reserve valve is closed but it is on a spring set to about 300-500 PSI (I know PSI isn't the right measurement but it it simpler this way and I'll just pretend that every thing is perfect and it is a perfect spring set exactly at 500) so as long as there is more that 500 PSI in the tank the spring is pushed back and air flows. When the tank pressure drops below the spring threshold pressure- the spring has more power than the air pressure and it closes. As the diver, you would pull on the rod (Which you don't have on and reaching behind your back is dificult) to release the last 500 psi by opening the reserve valve.

The problem is that your SPG will read the tank pressure quite well. It doesn't know about the 500 PSI thing. So if the reserve valve is mistakenly turned on or slips on or whatever, you'll find out only when your SPG goes from 501 to 0 in one breath. If you get the spring and valve seat/pin removed - the problem goes away.

If the valve is old it may slip and do you know which way is opened and closed? I remeber that up was off and down was on but I wouldn't bet on my recollection.

I hope that this helps. If I didn't make it clear enough just pop a message to me and I'll try again or I'll give you my AIM handle.

Matt

Walter
November 14th, 2001, 11:30 PM
J valves are fine as long as they are serviced and in good working order. Leave the J down and it works exactly like a K valve. I've heard of them getting knocked down when they should have been up, but never the other way around. If it were mine, I'd have it serviced, but as long as it's in good condition, I wouldn't replace it.

DSSW,

WWW™

TwoBitTxn
November 14th, 2001, 11:48 PM
OD,

I see your point. I missed the part in your first post about removing the guts and converting it to a K valve. I may just do that.

Down is open. The tag on the knob tells you what is open and what is closed. I'm not prone to panic when I run out of air either. I'm an ex volunteer fire fighter. Been there. I did almost freak in Level A training when my air wasn't turned on.

Thanks

Tom

Ontario Diver
November 14th, 2001, 11:54 PM
No problem Tom , as long as you know you can make a decision

Enjoy

miked
November 15th, 2001, 12:01 AM
Tom,
Glad you got a definite ID on the J valve.
OD's description of the functioning of the valve is right on the money. Having gotten my OW gertification with a J valve, I'd probably agree with swapping it or disabling it.
I can still remember the "thrill"???, during the OW certification dives, of feeling that sudden shutdown of the air supply, "calmly" reaching back for the pull rod, while praying that it was up at the start of the dive, and that there really was another 500 PSI in the tank.A trip to be avoided, if possible.
Please let us know what you do.
Miked

Rick Murchison
November 15th, 2001, 09:03 PM
Since no one has mentioned my number one reason to disable the "J" valve (or at least lockwire it to the "ON/down" position) I will - the inevitable short fill.
Should the tank be depleted to 300 psi or less and the valve be left up (or get put in the up position) and the person filling the tank doesn't notice it, it won't allow the tank to fill - putting pressure on the outside orifice won't force the valve open. So the fill station will show a full tank when only the fill whip is pressurized, and when you get ready to dive you'll have an empty.
And that won't make you very happy.
Rick

DivingGal
November 15th, 2001, 09:52 PM
here I popped on this thread 'cus I was curious about the topic.

The mix of humour and serious stuff kept me reading. Well done!!! I even found out a few new things.

TwoBitTxn
November 16th, 2001, 11:25 AM
Rick,

Wow thanks dude. Now that is good solid reasoning to disable the valve. I wonder honestly how many people running fill stations, especially when its a member of a younger generation, know that.

Tom

herman
November 16th, 2001, 01:45 PM
Hi Guys,

I have a "J" valve tank that I have been using for years. Mine has the valves opposite each other, looking down on the tank with the air opening tward me, the reserve knob is on the left and the open/close valve is on the right. I don't see any real need to replace the valve assuming it's in good shape. Trust me, you WILL know if the valve is in the "normal" diving position. Mine was in the "normal" position several years ago and scared the dickens out of my buddy. The spg will fluctuate up and down as you breathe, with a full tank mine goes from about 3000 to 1500 and back. The old timers at my LDS tell me that this is normal. That's the only difference I can tell with mine when it is in "normal" mode until it gets to about 300 psi (which I did on purpose in a guarry just to see how it worked). At that point, breathing got a lot harder but you could still inhale. When you flipped the lever to "reserve" it breathed normally. I keep mine as a conversation piece and it makes a great buddy "checker", flip it to normal and see how long it takes for him to have a cow. By the way, I dive mine on "reserve" all the time.....unless I have a new buddy....

jobowker
January 10th, 2002, 01:04 PM
When I was getting certified, most of the tanks were old LP steel 72's with j valves. No big deal. We all would turn on the air and flip the level down (no reserve). Since we started out that way, it was no big deal. Now that I'm used to k valves, I'm not certain that I would remember to flip the lever down when truning on the air, so if I owned one, I'd have the lever removed.

Rick L
January 11th, 2002, 07:31 AM
I still use a set of steel 72s with J valves!
I just leave them in the down pulled position!!
Rick L

Campana
January 11th, 2002, 09:39 AM
Don't worry. As a part time tank monkey, I can tell you that if the valve is in the up position, the tank won't fill, at all. You have to move it down. I can't imagine someone accidentally not filling your tank cause the J valve was in the up position.

They work fine. Just make sure they're in the down position as part of your predive check.

Replacing it would cost about $35 for a K valve, IF the tank has a 3/4" neck opening. If it's the old 1/2" or whatever, it's hard to find valves and your stuck with it.

I would just keep it and not worry. I've got three or four tanks with J valves and never had a problem. Our shop has several, same deal.

Rick Murchison
January 11th, 2002, 08:02 PM
Originally posted by Campana
I can't imagine someone accidentally not filling your tank cause the J valve was in the up position.

This usually happens where lots of tanks are being filled several at the time, so noticing that six tanks are filling a little more quickly than usual does escape the filler.
Like many things in life, there are two kind of folks who use "J" valves - those who have gotten the short fill, and those who will.
Rick

devjr
January 14th, 2002, 04:41 PM
In the 50's, there were three kinds of valves available, the K valve, J valve and R valve. The K valve was a straight post type valve with knob on the top, the J valve, a modified post valve, had a knob on the top and reserve lever on the side; the "R" was a post valve with combined "on" and "reserve" built into a single knob on top. This unique valve had two outlets set vertically inside the teflon ring(before O rings). The smaller hole was for air supply, the other for reserve supply. Turning the knob all the way open allowed air to pass through the larger hole, thus releasing the "reserve".

By 1959, the R valve was dropped from the product line. Around this time also, a maverick inventor with the Waterlung company, developed a low profile valve with the "on" knob on the side and the reserve lever in the usual left hand side position. This is the type valve our novice friend is inquiring about.

Yes, for brevity we called the valves by their catalog letters and, in truth, I am one of those who started the practice. USD called those valves NON RESERVE, CONSTANT RESERVE and POSITIVE RESERVE. Strangely, with these new low profile designs, the valves themselves began to appear somewhat similar to their original catalog designations.

As a teenager, I had no idea, that 45 years hence, divers would not only continue to follow but extend this idiom.

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